[PR100127] Test for coroutine header in clang-compatible tests

[Alexandre Oliva via Gcc-patches]

The test is compatible with clang as well as gcc, but ISTM that
testing for the __clang__ macro is just as potentially error-prone as
macros that used to be GCC-specific are now defined in compilers that
aim for GCC compatibility.  Use a __has_include feature test instead.

Regstrapped on x86_64-linux-gnu.
Tested on arm-vxworks7 (gcc-12) and arm-eabi (trunk).  Ok to install?

for  gcc/testsuite/ChangeLog

        PR c++/100127
        * g++.dg/coroutines/pr100127.C: Test for header rather than
        compiler macro.
---
 gcc/testsuite/g++.dg/coroutines/pr100127.C   |    2 +-
 gcc/testsuite/g++.dg/coroutines/pr100772-a.C |    2 +-
 gcc/testsuite/g++.dg/coroutines/pr100772-b.C |    2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/gcc/testsuite/g++.dg/coroutines/pr100127.C 
b/gcc/testsuite/g++.dg/coroutines/pr100127.C
index 374cd710077af..1eaa72ff0acdd 100644
--- a/gcc/testsuite/g++.dg/coroutines/pr100127.C
+++ b/gcc/testsuite/g++.dg/coroutines/pr100127.C
@@ -1,4 +1,4 @@
-#ifdef __clang__
+#if __has_include(<experimental/coroutine>) // for __clang__
 #include <experimental/coroutine>
 namespace std {
   using namespace std::experimental;
diff --git a/gcc/testsuite/g++.dg/coroutines/pr100772-a.C 
b/gcc/testsuite/g++.dg/coroutines/pr100772-a.C
index a325d384fc390..724c377c82e5b 100644
--- a/gcc/testsuite/g++.dg/coroutines/pr100772-a.C
+++ b/gcc/testsuite/g++.dg/coroutines/pr100772-a.C
@@ -1,5 +1,5 @@
 //  { dg-additional-options "-fsyntax-only " }
-#ifdef __clang__
+#if __has_include(<experimental/coroutine>) // for __clang__
 #include <experimental/coroutine>
 namespace std {
   using namespace std::experimental;
diff --git a/gcc/testsuite/g++.dg/coroutines/pr100772-b.C 
b/gcc/testsuite/g++.dg/coroutines/pr100772-b.C
index 6cdf8d1e529e5..4cf31e5f9e0c2 100644
--- a/gcc/testsuite/g++.dg/coroutines/pr100772-b.C
+++ b/gcc/testsuite/g++.dg/coroutines/pr100772-b.C
@@ -1,4 +1,4 @@
-#ifdef __clang__
+#if __has_include(<experimental/coroutine>) // for __clang__
 #include <experimental/coroutine>
 namespace std {
   using namespace std::experimental;

-- 
Alexandre Oliva, happy hacker                https://FSFLA.org/blogs/lxo/
   Free Software Activist                       GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
but very few check the facts.  Ask me about <https://stallmansupport.org>